Three areas, binocular vision, motion sensitivity and static ocular rotations are analyzed from a three-dimensional geometrical perspective. This perspective, in turn, provides an important set of organizing concepts within which to conduct a number of fundamental and clinical investigations. These include a nonius determination of binocular correspondence over the whole binocular field, an attempt to replicate the reported up-down anisotropy of stereopsis with conventional stereograms, and a systematic assessment of the effect of spatio-temporal changes in vertical disparity on fusion and stereopsis in dynamic random dot stereograms. In addition, the spatial resolving power of human motion sensitivity will be investigated using two new visual displays, a random dot moving grating and a dynamically distorting sinusoidally modulated luminance grating. Finally, the three-dimensional nature of ocular rotations will be measured for normal observers in convergence and for selected patients having strabismus, before and after surgery.